Chimpanzees take antibiotics on their own | The science

A few weeks ago, it was reported that an orangutan was applying a medicinal plant poultice to a disfiguring wound on his face. Now, thousands of miles away on another continent, it turns out that another great ape, the chimpanzee, uses a range of vegetables, from leaves to tree bark, to treat its ailments. Analysis of these plants, some of which are widely used in traditional medicine, showed that most of them have antimicrobial activity and, thirdly, anti-inflammatory activity. The authors of this work believe that apes may one day help people discover new drugs.

Budongo Forest Reserve (Uganda) is home to several chimpanzee communities. Two of them, Sonso and Vaibira, have been accustomed to the presence of scientists studying two populations (the first of 68 individuals and the second of 105) since the last century. From time to time they have been seen eating plants of unknown or no nutritional value. Suspecting its possible medicinal use, the team collected dozens of samples from 17 parts of 13 different species (from some they collected leaves, bark or dead wood) that were not part of their normal diet. In parallel, they analyzed the stool and urine of both groups to identify pathologies, especially monitoring the behavior and condition of 51 of them.

As detailed in a scientific journal PLOS ONEThe samples were analyzed to determine their anti-inflammatory and antibiotic properties at the Neubrandenburg University of Applied Sciences (Germany) in the laboratory led by Dr. Fabien Schulz, co-author of the study. They obtained 53 extracts using different methods and then analyzed their pharmacological effects.

“We tested these extracts for their antibacterial and anti-inflammatory effects,” says Schultz, an ethnopharmacologist who has spent many years studying the connections between traditional medicine in human societies and medicinal plants consumed by primates. “In our antibiotic trials in vitro, we examined the effects of extracts on the growth of 11 different strains of bacterial pathogens. These included clinical isolates of so-called ESKAPE pathogens, which WHO considers one of the biggest threats to global health,” he adds. Among the bacteria there are some pathogenic ones, such as coliand multidrug-resistant such as Staphylococcus aureus or Klebsiella pneumonia. “All strains used in our study were resistant to multiple drugs, often to the most important existing antibiotics,” concludes the German researcher. They almost succeeded: 45 plant extracts (88%) showed at least some antibacterial activity at the lowest concentration tested against at least one strain.

They showed that the collected plants had antibacterial effects, but as Schultz points out, this “tells us nothing about the potency of these herbal remedies; there are simply active ingredients that cause these effects.” Efficacy was assessed using dose-response analyses. Thus, they identified the most powerful extracts by isolating an extract obtained from dead wood. Alstonia bunei, a deciduous tree native to much of sub-Saharan Africa and used as medicine by many human communities. In experiments, its greatest inhibitory ability was shown against bacteria that are feared in hospitals. S. aureusand another, which is characteristic of the human digestive system, can become pathogenic, causing meningitis in newborns, Enterococcus faecium. They also demonstrated greater antibiotic capacity against these bacteria and coli bark and resins Haya Antoteka, a big tree. Over the past two years of monitoring, researchers have observed several chimpanzees with intestinal parasites, eating the wood of one and the bark and resin of another.

“A chimpanzee with an injured arm was looking for fern leaves that have strong anti-inflammatory properties.”

Elodie Freimann, researcher at the University of Oxford

Until now, it was known that some chimpanzee communities consumed leaves or other plant parts to fight intestinal parasitic infections. In the case of many leaves, the healing effect is mechanical in nature, there is no active substance: incapable of digestion and inhabited by rough trichomes on their surface, they carry along intestinal worms such as nematodes. But the use of plants with antibiotic activity has not been as extensively documented. And not just antibiotics.

According to Oxford University researcher and first author Elodie Freimann, “a chimpanzee with an injured arm was looking for fern leaves with strong anti-inflammatory properties; “No other individuals around it were eating ferns, and in 30 years of observation this has only been observed once.” The type of fern was specifically Cristella parasitica. A third of the species analyzed had anti-inflammatory or analgesic effects. While it’s difficult to close the loop and link intentionality to action and outcome, Freiman said, “this suggests that chimpanzees may have sought out ferns for their anti-inflammatory properties.” They’re going to study this further to confirm that, at least in these communities, they look for certain plants and not others when they have a certain ailment and not another.

“It is important to remember that wounds are not the only ailments that animals suffer from, and that there will be internal diseases for which animals will have to self-medicate,” recalls the Oxford researcher. “It can be more difficult to study than wounds because you can’t physically see what’s going on in the animal you’re studying, so it requires taking a multidisciplinary approach, analyzing behavioral episodes along with health data and pharmacological results,” he adds. . Linking the history of these chimpanzees with the history of the orangutan RakusFreymann concludes by emphasizing: “The natural world is full of drugs that we, as well as our non-human neighbors, depend on. If we want to keep these animals safe, we have to protect their first aid kit.”

Even being selfish. Fellow researcher, ethnopharmacologist Schultz, who is currently researching the use of medicinal plants by mountain gorillas, recalls that “finding a highly successful medicine from natural materials is often like looking for a needle in a haystack.” however, our work has contributed to early-stage drug discovery.” Of course, there is still a lot to be done; the extract may contain over 1000 different substances. “We don’t know (yet) what substances are present, whether they are new to science or how strong they are. There may also be synergistic effects, that is, the effect is caused by a combination of substances, and not just one,” recalls the German scientist. Moreover, they provided only scientific evidence of its effectiveness. in vitro and the active ingredient(s) have yet to be isolated and determined if they will be applicable in animal testing, but, Schultz concludes, “it’s a very long way to go, but in theory humans can learn from our closest animal ancestors and, some “One day human lives can be saved thanks to the knowledge of chimpanzees.”

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